Download Limiting Factor Principle

DNA (OUTPUT)
Why is NPP a more accurate
measure of plant biomass growth
than GPP?
Turn in chapter 5 in file by end of day.
HOMEWORK
 Book club reply to first post due by 9/10; 9/11
 ONLY Food for Thought due 9/12 ; 9/15
 Ocean Acidification Lab analysis and conclusion first
draft due 9/12 ; 9/15
 Oh Deer questions due 9/12 ; 9/15
AGENDA
1.
2.
3.
4.
5.
6.
Unit 1 Test
Gallery Walk?
Notes
Mix Freeze Pair
Notes
“How many squirrels” activity
 Things to consider in your analysis:
WHO DOES WHAT?
 What is the percent change in mass for each of
your shells?
 Things to consider in your conclusion:
 Summarize what you learned
 Any sources of error?
 Take it a step further!: research the effects of
ocean acidification on other types of marine life.
 Your analysis and conclusion are due 9/12 ; 9/15
WHO DOES WHAT?
 Each individual group member is expected to write
an analysis and a conclusion (individual work grade
is based on completion).
 The group will peer-edit and individuals will revise.
 ONE mini-report will be randomly selected from
the group and graded. That grade will be a shared
group grade. Revised reports must be typed.
ECOSYSTEMS: INTRODUCTION TO
POPULATION DYNAMICS
GALLERY WALK
 Put your brochures on your table
 Take your scratch paper and cut it in half
 You will be leaving TWO comments today
 The comments need to be MEANINGFUL
 Leave YOUR NAME on your comment
 You will get 1 snooty song to complete this gallery walk
YOU MAY USE THESE SENTENCE FRAMES
 “I didn’t realize …”
 “The illustrations were convincing because…”
 “I learned ________ from your brochure”
 “_____ on your brochure was a strong
element but ______ might need
improvement”
POPULATION DYNAMICS
 We will be focusing on:
 The major characteristics of populations
 How do populations respond to environmental
change?
 How do species differ in their reproductive habits?
POPULATION DISTRIBUTION
 Population
distribution =
dispersion
 3 general patterns:
clumping, uniform
dispersion, random
dispersion
CHANGES IN POPULATION SIZE
 Populations increase through births and immigration
and decrease through deaths and emigration
 Population change = (births + immigration) – (deaths
+ emigration)
AGE STRUCTURE
 Age structure – the proportions of individuals at
various ages
 Age structure can affect how rapidly a population’s
size increases or decreases
 Prepreproductive, reproductive, postreprodutive
OH, DEER!
 I will show you our data from the Oh Deer!
Activity
 Copy it down on your own handout
 Take 30 seconds to QUIETLY identify any patterns
in your data
OH, DEER! QUESTIONS
 Answer the “Oh Deer!” questions on a separate
sheet of paper (graph paper is best!)
NO POPULATION CAN INCREASE ITS SIZE
INDEFINITELY
Elbow partners:
What things can limit population growth?
RANGE OF TOLERANCE
A range of tolerance - the range of
chemical and physical conditions that must
be maintained for populations of a species
to stay alive and grow, develop, and
function normally.
WHAT DOES THIS MEAN?
Some populations need bright sunlight
Some populations need a hot environment
Some populations need wet conditions
FACTORS THAT LIMIT POPULATION GROWTH
 The availability of matter and energy resources can
limit the number of organisms in a population.
 Limiting factor – single factor that limits the
growth, abundance, or distribution of the
population of a species in an ecosystem
LIMITING FACTOR PRINCIPLE
 Limiting Factor Principle - Too much or too
little of any abiotic factor can limit or prevent
growth of a population, even if all other factors are
at or near the optimum range of tolerance
LIMITING FACTOR PRINCIPLE
LIMITING FACTOR PRINCIPLE
 Illustrate the limiting factor principle with an
organism of your OWN CREATION
 Examples of limiting factors:
Temperature
pH
Salinity
Exposure to sunlight
Water (think
plants)
Soil nutrients
LIMITS ON POPULATION GROWTH
 No population can increase its size indefinitely
 Biotic potential – a population’s capacity for
growth
 Intrinsic rate of increase (r) – the rate at which a
population would grow if it had unlimited
resources
LIMITS ON POPULATION GROWTH
 Some species have really high biotic potential
 However, in the real world, no population can grow
indefinitely
 A population reaches some size limit imposed by
limiting factors such as light, water, living space, or
nutrients
 There are always limits to population growth in
nature.
LIMITS ON POPULATION GROWTH
 Environmental resistance: all factors that act
to limit the growth a population
 Carrying capacity (K) – the maximum
population of a given species that a particular
habitat can sustain indefinitely without degrading
the habitat
CARRYING CAPACITY (K)
 K is determined by the biotic potential and
environmental resistance
ANALYZE THIS GRAPH
 At what level do
the deer reach their
carrying capacity?
 How do you know
what is the K?
 What explains
months 4, 5, 6, 7?